1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ARM64 CPU idle arch support
4  *
5  * Copyright (C) 2014 ARM Ltd.
6  * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
7  */
8 
9 #include <linux/acpi.h>
10 #include <linux/cpuidle.h>
11 #include <linux/cpu_pm.h>
12 #include <linux/of.h>
13 #include <linux/of_device.h>
14 #include <linux/psci.h>
15 
16 #ifdef CONFIG_ACPI
17 
18 #include <acpi/processor.h>
19 
20 #define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
21 
psci_acpi_cpu_init_idle(unsigned int cpu)22 static int psci_acpi_cpu_init_idle(unsigned int cpu)
23 {
24 	int i, count;
25 	struct acpi_lpi_state *lpi;
26 	struct acpi_processor *pr = per_cpu(processors, cpu);
27 
28 	if (unlikely(!pr || !pr->flags.has_lpi))
29 		return -EINVAL;
30 
31 	/*
32 	 * If the PSCI cpu_suspend function hook has not been initialized
33 	 * idle states must not be enabled, so bail out
34 	 */
35 	if (!psci_ops.cpu_suspend)
36 		return -EOPNOTSUPP;
37 
38 	count = pr->power.count - 1;
39 	if (count <= 0)
40 		return -ENODEV;
41 
42 	for (i = 0; i < count; i++) {
43 		u32 state;
44 
45 		lpi = &pr->power.lpi_states[i + 1];
46 		/*
47 		 * Only bits[31:0] represent a PSCI power_state while
48 		 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
49 		 */
50 		state = lpi->address;
51 		if (!psci_power_state_is_valid(state)) {
52 			pr_warn("Invalid PSCI power state %#x\n", state);
53 			return -EINVAL;
54 		}
55 	}
56 
57 	return 0;
58 }
59 
acpi_processor_ffh_lpi_probe(unsigned int cpu)60 int acpi_processor_ffh_lpi_probe(unsigned int cpu)
61 {
62 	return psci_acpi_cpu_init_idle(cpu);
63 }
64 
acpi_processor_ffh_lpi_enter(struct acpi_lpi_state * lpi)65 int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
66 {
67 	u32 state = lpi->address;
68 
69 	if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
70 		return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(psci_cpu_suspend_enter,
71 						lpi->index, state);
72 	else
73 		return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
74 					     lpi->index, state);
75 }
76 #endif
77